1. Field of the Invention
The present invention relates to light emitting blocks such as can be used to provide light to a display device, e.g. a liquid crystal display.
2. Description of the Related Art
Liquid crystal displays (LCDs) are a type of flat panel displays. The LCDs are popular for being thin, light, having a low driving voltage and low power consumption, and for other advantages as compared to other types of displays such as cathode ray tube (CRT), plasma display panel (PDP), and others. In particular, the LCDs are widely employed in electronic devices such as monitors, laptop computers, cellular phones, television sets, etc. An LCD includes an LCD panel that displays images by setting the light-transmitting ratio of liquid crystal molecules, and also includes a backlight assembly disposed below the LCD panel to provide the LCD panel with light.
The LCD panel includes an array substrate, another substrate opposite to the array substrate, and a liquid crystal layer between the two substrates. The array substrate includes signal lines, thin-film transistors (TFTs) and pixel electrodes. The substrate opposite to the array substrate contains a common electrode.
The backlight assembly may employ cold cathode fluorescent lamps (CCFLs) as a light source. Presently it is common for the backlight assembly to employ light-emitting diodes (LEDs) having low power consumption and high color reproducibility.
The backlight assembly may generate light by using individually controlled light-emitting blocks arranged in a matrix so as to enhance the contrast ratio and decrease power consumption. Each light-emitting block may have a number of LEDs.
In order to individually control the light emitting blocks, the backlight assembly may include a plurality of row switches for individually controlling each row of the light-emitting blocks and a plurality of column switches for individually controlling each column of the light-emitting blocks. The row and column switches allow individual control of each light-emitting block. However, additional control is desired over the luminance level of the emitted light.